GLASS is a POLARIN and Tarfala Research Station (TRS) funded project that will design, test and disseminate best-practice sampling strategies for glacier algal blooms, creating the rigorous ground-truth datasets our community needs to calibrate and validate satellite and model based bloom assessments. This project involves extensive high-resolution sampling of glacier algal blooms through space and time coupled with advanced geostatistical techniques, to determine the spatial structure of blooms and how this evolves across glaciers and throughout melt seasons. Fieldwork runs through July to September 2025 at Tarfala Research Station (Sweden) with repeat sampling across Storglaciären, led by MicroLab group lead Chris Williamson and PhD student Benjamin Johnson.
Why this matters
Glaciers are retreating quickly, yet they host diverse microbial communities. Glacier algae form the basis of supraglacial food webs, producing widespread blooms during summer melt seasons, driving carbon and nutrient cycling and contributing to ice melt through albedo feedback. Despite their importance, we still lack spatially resolved ground truth measurements of how glacier algal blooms develop across glaciers and throughout melt seasons. This limits our ability to calibrate and validate the larger-scale remote sensing or modelling of blooms that are needed to understand their importance and impacts at globally-relevant scales. GLASS directly tackles this knowledge gap, undertaking high-resolution sampling and analysis of glacier algal blooms to develop a detailed understanding of how their spatial structure evolves, translating this information into actionable methods for bloom monitoring by the wider scientific community (CASP-ICE network).
What GLASS will do
We will develop and validate a standardised sampling methodology that captures the true spatial heterogeneity of glacier algal abundance across early, peak, and late bloom stages. Specifically, we will:
- Make fine-scale, nested abundance measurements across Storglaciären and throughout the summer melt season.
- Use semivariograms to quantify the spatial structure (nugget, sill, range) of our glacier algal blooms and determine optimal sampling intervals.
- Test Kriging and Bayesian strategies for adaptive, information-efficient sampling through time.
- Deliver the first spatially resolved picture of bloom propagation in surface ice.
- Publish best-practice recommendations for the community and future monitoring.
Where & when
Fieldwork takes place on Storglaciären (Sweden) with three short campaigns: 7–17 Jul, 7–17 Aug, 7–17 Sep 2025. The Tarfala Research Station (TRS) provides access and logistic support throughout.
Expected Outcomes
Open datasets: spatially resolved algal abundance across Storglaciären at three bloom stages.
Validated sampling blueprint: recommended spacing, effort, and adaptive rules that generalise to other sites.
Community SOPs: accessible protocols shared via CASP-ICE for rapid uptake by glaciology and microbiology teams, including non-specialists involved in mass-balance or cryosphere monitoring.
High-impact papers establishing state-of-the-art methods for mapping bloom heterogeneity and informing global upscaling.
